First make the courgette pesto: put all the ingredients in a small food processor, then whizz until you get a coarse paste. Put it aside.
Using a vegetable peeler cut the courgette into long, thin slices. Cut the fish in half, rub with salt & pepper, then carefully wrap with 2-3 courgette slices.
Heat the oil in a frying pan. When hot, fry the wrapped fish for 2-3 minutes on each side until the courgette is crispy and the fish is cooked through.
Brush the fried fish with the pesto, then serve with vegetables/salad and the remaining pesto on the side.